Numerous assembly processes for electronic assemblies suitable for large-scale production are widespread in the art. Substantially, each assembly process provides for mounting one or more electronic devices onto an electronic board (e.g., a Printed Electronic board or PCB). Typically, each electronic device comprises one (or more than one) chip of semiconductor material on which an actual electronic component (or an electronic microcircuit) is integrated. The chip is encapsulated in an insulating package to be insulated and protected from the external environment. The package exposes conductive pins, which are coupled with corresponding terminals of the chip. The pins of the package are welded to conductive tracks formed on an insulating substrate of the electronic board. This allows the interaction between the electronic component and other electronic devices, mounted on the electronic board in a similar manner, through the tracks suitably connected among them.
For example, a known welding technique is the wave soldering technique. In this case, the electronic devices are initially glued onto the electronic board by means of an adhesive paste, so that the pins of the electronic device correspond to welding regions of the tracks of the electronic board. Subsequently, the assembly thus obtained is arranged above a bath of molten solder paste, with a surface of the electronic board (on which the electronic devices are glued) facing downwards. The assembly is then flooded with a wave of molten solder paste, which brushes the electronic board so as to bind to the welding regions of the electronic board thereby welding the pins of the electronic devices thereto (without affecting the rest of the assembly made of insulating material).
The wave soldering technique described above, however, may be problematic with certain types of electronic devices. For example, this may occur in the case of electronic devices in Surface-Mount Technology or SMT, and in particular in the case of electronic devices known in the art with the name of “No-Lead” or “Micro-Lead”, in which the pins are made by conductive areas exposed on a mounting surface of the package of the electronic device for the mounting on the electronic board. Indeed, a gap that is formed after the gluing of the package, between the pins of these electronic devices and the welding regions, may be too narrow to allow the wave of solder paste to penetrate optimally—in particular, in case of pins with a relatively large surface.
In addition, the operating temperature of the electronic component (especially if of small size and/or high power) may be very high and this may reduce the performance of the electronic component, possibly up to a breakage thereof or in any case reducing its useful life.
In the art it is known to provide a heat sink (or more) connected to the chip and facing the mounting surface of the package so as to dissipate the heat onto the electronic board on which the electronic device is mounted. Furthermore, it is known to thermally connect a heat sink (or more) to the electronic device, so as to facilitate an exchange of heat with the external environment. Typically, the heat sink is connected to the electronic device after the latter has been mounted onto the electronic board; for example, the heat sink is glued directly to the package, or it is welded and/or screwed to the electronic board thereunder.
However, this requires a dedicated mounting operation of the heat sink, which entails a number of additional steps in a manufacturing process of such electronic assemblies, and requires corresponding machinery and/or technicians to perform them, with a consequent increase of the manufacturing cost thereof.